Higher pain sensitivity and lower muscle strength in postmenonpausal women with early rheumatoid arthritis compared with age-matched healthy women – a pilot study

Abstract

Purpose: The purpose of the study was to examine muscle strength and pain sensitivity in postmenopausal women with and without RA. Methods: Ten women with and ten without early RA were recruited. All were postmenopausal, and did not use hormone replacement therapy. Measurements of isokinetic muscle strength in knee flexors/extensors, hand grip strength, timed standing, pressure pain thresholds (PPT), suprathreshold pressure pain, and segmental and plurisegmental endogenous pain inhibitory mechanisms during muscle contraction were assessed. Results: Participants with early RA were weaker in knee flexors, in hand grip strength and they needed more time for the timed standing. Women with early RA had higher sensitivity to threshold pain and suprathreshold pressure pain compared to women without RA. PPTs increased in the contracting muscle as well as in a distant resting muscle during static contractions in both groups. Conclusions: Our results indicate differences in muscular strength between postmenopausal women with and without RA. Furthermore, women with RA had decreased PPT and hyperalgesia, but no dysfunction of segmental or plurisegmental pain inhibitory mechanisms during static exercise compared to healthy controls. The normal function of endogenous pain inhibitory mechanisms despite chronic pain in women with RA might contribute to the good effects of physical activity previously reported.

Implications for Rehabilitation

• Difference in muscular strength between postmenopausal women with and without (rheumatoid arthritis) RA is present in early disease despite low disease activity.

• Women with RA have decreased pressure pain thresholds and hyperalgesia, but no dysfunction of segmental and plurisegmental pain inhibitory mechanisms.

• The normal function of endogenous pain inhibitory mechanisms despite chronic pain in women with RA might contribute to the good effects of physical activity in this group of patients.

Keywords::

• Arthritis
• Body function
• Female
• Pain measurement
• Pain threshold

Acknowledgement

The Swedish Rheumatism Association, the Promobilia Foundation, Combine Sweden, Regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institutet.

Declaration of Interest: The authors report no declarations of interest.